21212110121 has 2 divisors, whose sum is σ = 21212110122. Its totient is φ = 21212110120.

The previous prime is 21212110109. The next prime is 21212110147. The reversal of 21212110121 is 12101121212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13848582400 + 7363527721 = 117680^2 + 85811^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212110121 - 2⁶ = 21212110057 is a prime.

It is a super-3 number, since 3×21212110121³ (a number of 32 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21212110096 and 21212110105.

It is not a weakly prime, because it can be changed into another prime (21212110021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606055060 + 10606055061.

It is an arithmetic number, because the mean of its divisors is an integer number (10606055061).

Almost surely, 2^21212110121 is an apocalyptic number.

It is an amenable number.

21212110121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212110121 is an equidigital number, since it uses as much as digits as its factorization.

21212110121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21212110121 its reverse (12101121212), we get a palindrome (33313231333).

The spelling of 21212110121 in words is "twenty-one billion, two hundred twelve million, one hundred ten thousand, one hundred twenty-one".